Computer programs can be used to produce graphical images that can be rendered and displayed on an output device. Two such classes of programs are illustration applications and animation applications. An illustration application can be used to generate original graphics or combine original and existing graphics to produce a graphics image (an electronic document or illustration) that can be displayed on a static output device. An animation application can be used to produce a composition that includes graphics that can be animated using one or more effects to produce a result that can be played on a dynamic output device.
Illustrations and compositions produced using conventional illustration and animation applications include simple objects that are combined to form a final illustration or composition. A simple object can be a path, text, or other vector art object or an image art object and typically includes several properties. Properties can include paint effects such as strokes and fills for paths, vector effects-such as zig-zag and scale, color blending effects such as transparency and darkening, and image effects such as fade, blur, and watercolor.
Two basic properties of a simple vector object are its stroke and fill attributes. A stroke is a representation that follows the outline of a path. Strokes can have attributes such as color, width and dash pattern. For example, in the Adobe Illustrator® program, available from Adobe Systems Incorporated of San Jose, Calif., a stroke can be a solid color, a pattern or a brush and can include attributes such as weight, cap, join and dashed. A fill is an instruction for painting the interior of a path with a solid or variegated color, such as a repeating pattern, a color gradation or a randomized arrangement. A fill might be a solid color, a gradient, a gradient mesh or a pattern. In conventional illustration and animation programs, every simple object can have a single stroke and a single fill.
When objects are combined—into a layer, for example—the rendered appearance of the objects can be affected by properties attached to the combination. Otherwise, objects are typically rendered for display in accordance with their individual properties.